Wednesday, October 24, 2007

30 Minute Puzzle - Sand watches

30 Minute Puzzle
Here is another riddle like we earlier had with the Burning Rope timer with a different concept and sure a good one!!
Lets move right away to the brain teaser:
You are given two "hourglasses(sand watches)", one of which will empty in 9 minutes, and one in 13 minutes. You need to measure a time interval of exactly 30 minutes. Is it possible?